The technology giant, which is weighing a sale of all or parts of its business, has attracted the attention of several buyout shops and strategic investors, the latest being private equity firm Silver Lake, which has already approached Yahoo about a potential bid, two people close to Yahoo said.

Silver Lake, which is working with the venture firm Andreessen Horowitz, has been quietly studying a possible bid for the last six months, one person said. Other potential bidders for Yahoo include Microsoft and China's Alibaba Group.

Yahoo, Microsoft, Silver Lake Partners and Andreessen Horowitz declined to comment. Individuals close to the matter spoke on the condition they not be identified because the talks were confidential.

For Yahoo, which rejected a bid from Microsoft in 2008, the crowd of suitors is a familiar one. According to two people with knowledge of the situation, Providence Partners and Peter Chernin, the former chief operating officer of the News Corporation, also are studying a possible bid. This year, Chernin approached Yahoo about a possible deal, according to one person. But he was rebuffed. Silver Lake, which recently profited from the sale of Skype to Microsoft, has long been said to be a potential buyer.

The renewed interest in Yahoo comes at a critical juncture, as rivals like Google and upstarts like Facebook have boomed, leaving Yahoo struggling to keep pace.

Last week, in a moment that starkly portrayed its troubles, the board dismissed its chief executive, Carol A. Bartz, by phone. Bartz, well known in Silicon Valley for her brash attitude and comfort with expletives, had joined Yahoo less than three years earlier.

Yahoo's board discussed Silver Lake's approach during its meeting on Wednesday and hired Allen & Company as its investment bank for a continuing review of its business.